Dr. Leonard has devoted most of his career to the study of children with language disorders, with special emphasis on a group of children whose language disorders are especially surprising, because these children appear relatively typical in their intellectual development and neurological functioning, and they exhibit normal hearing and adequate social skills. Approximately 5-7% of children show this type of disorder, referred to as “specific language impairment” (SLI). These children develop language slowly and are at significant risk for reading and other academic difficulties by school age, and can show residual deficits into adulthood that hinder economic as well as social well being. Twin studies reveal a significant hereditary component in SLI; however, genetic studies also reveal that this impairment is likely to be multifactorial.

Dr. Leonard’s focus has been on the detailed language symptoms of SLI. Since 1971, he has conducted research on these children’s ability to acquire new words, pronounce speech sounds, use language in conversations, and apply the rules of grammar when both speaking and listening to language. Beginning in 1985, Dr. Leonard has undertaken research of a cross-linguistic nature – examining the language symptoms of children with SLI who are acquiring different languages. In collaboration with researchers in seven different countries, Dr. Leonard has studied children with SLI who were acquiring English, Italian, Hebrew, Swedish, Spanish, Cantonese, Finnish, and Hungarian. He was the first to point out that the same fundamental problem can lead to widely varying language symptoms depending on the typology of the language. Dr. Leonard was also a pioneer in the use of treatment paradigms to test competing theories of SLI. By helping children acquire particular details of language through therapy and observing whether corresponding changes occurred in other symptoms, he was able to significantly reduce the number and types of theories viewed as viable explanations for this disorder.

Dr. Leonard’s research has been funded by the National Institutes of Health for 26 years. He has published more than 175 research articles, 45 chapters in edited volumes, and two books. His 1998 book Children with Specific Language Impairment, published by MIT Press, is widely recognized as a classic. Dr. Leonard has received editors’ awards for several of his research articles, and, in 1995, received the prestigious Council of Editors Award from the American Speech-Language-Hearing Association for his sustained record of scholarship. During his career, Dr. Leonard has served on Study Sections and Advisory Panels for the National Institutes of Health, has been an editor and member of numerous editorial boards, and is currently the Chair of the Publications Board of the American Speech-Language-Hearing Association. Dr. Leonard has also served as mentor for many doctoral students and post-doctoral fellows. These individuals have gone on to become leading researchers in the field and hold faculty positions in many of the top institutions in the country.

The Purdue Chapter of Sigma Xi is pleased to recognize Professor Laurence Leonard with its 2007 Faculty Research Award, an award designed to honor a person of this caliber.